CD34 and schwannoma: On an immunohistochemical level, schwannomas, like most neurogenic tumors, show strong positivity for the S-100 protein, an important marker of the CNS [1,2,4,5,6,10,11,16,21,23,26]; Martins et al., in their 2007 paper, also reported positivity for EMA (Epithelial Membrane Antigen), fibronectin, CD34, and collagen, especially when the tumor is found in its encapsulated form [2].